The Kansas Center for Research in Mental Retardation and Related Aspects of Human Development (MRRC) is committed to the resolution of the problems of mental retardation and developmental disabilities. The efforts of the Kansas MRRC are based on both behavioral and biological research conducted in a variety of settings and with a range of populations. Six thematic areas of research are proposed for the next five years. Administration support core unit and four scientific cores provide a range of support services to MRRC investigators.